MX2007015351A

MX2007015351A - Protective cap for industrial footwear.

Info

Publication number: MX2007015351A
Application number: MX2007015351A
Authority: MX
Inventors: Roberto Zitzumbo Guzman; Fernando Chico Ruiz; Carlos Armando Fuentes Aragon; Ramon Alberto Ayala Medina; Constantino Vidal Guerrero; Roberto Munoz Almaguer
Original assignee: Internac De Calzado Ten Pac S
Priority date: 2007-12-05
Filing date: 2007-12-05
Publication date: 2008-09-18
Also published as: WO2009072857A1; US20140115795A1; CA2707574C; EP2223621A4; US10045586B2; EP2223621A1; US20100236105A1; ES2535008T3; EP2223621B1; CO6280392A2; CA2707574A1

Abstract

The present invention refers to a monolithic cap for safety footwear, which forms a concave-shaped frame including a front wall with lateral walls connected to each side portion thereof and which upper edge portions are attached together by a concave-shaped surface following the shoe last shape. The inventive cap has a particular area located on the flap edge portion thereof useful for housing a comfort stripe, which provides comfort and improves the footwear appearance. The design of the present invention resists impact tests of from about 101.7 Joules to 146.7 Joules (10.40 kgf-m to 14.95 kgf-m) and compression tests of from about 11130 Newton to about 14710 Newton (1135 kgf-m to about 1500 kgf-m), thus leaving a free height of from about 11.0 mm to about 14.0 mm in the whole finished shoe and not only over the cap tip.

Description

PROTECTIVE HELMET FOR INDUSTRIAL SHOES DESCRIPTION Background and Field of the invention To protect a worker who performs a productive activity in the industry, a one-piece helmet has been designed for protective work footwear where said helmet is specifically designed to protect the five toes from impacts and crushes caused by falling objects. The invention relates to a one-piece helmet for safety shoes that forms a concave 180 ° frame that houses an internal cavity supported by a horizontal inner eyebrow that covers the entire internal part of the helmet perimeter from 5 to 7 mm. wide, the concave frame is composed of a front wall with side walls connected on both sides and whose upper edges are joined by a concave surface following the silhouette of the last; the helmet is previously prepared with the fixation in the mouth of the same with a strip of synthetic material called fade and placed on the footwear through an insert fitted to the tip of the last clothed, meaning as last dressed a previous fixation of an element called plin the bottom of the last and another element adjusted three-dimensionally to the tip of the last called lining, completing the fixing of the helmet through a layer of wrapping material fitted to the entire outer surface of the helmet. The upper surface has an edge on the side opposite the front wall that presents a fading. In addition, the invention relates to a method for calculating and designing a helmet from a last. It is known that the Mexican company FOOTMEX DE MÉXICO S.A. of CV. produces a commercial helmet designed in two alternative materials, which are offered to the market as economic and high impact, basing their designs on two helmets of commercial dimensions known as model 600 and 630. The registration of Mexican model No. 796, grd the July 13, 2000, to the company Calzado Van Vien, SA de CV, refers to an armored cap for protective footwear formed by a section in the form of a hollow semi-parabolic dome made of high strength steel sheet designed to house and protect the Toe of the user of impacts of forces, where the section itself is bent at its lower end to form a horizontal eyebrow that covers the entire perimeter by the internal part of the cap and because the ends of the inner horizontal eyebrow possess a welded bridge to the underside of the eyebrow whose function is to provide structural support to the armored bushing, to avoid its collapse or crushing under the impact of a force of significmagnitude. In the Mexican patent number 225317, award date January 4, 2005, grd to H. BROWN BROWN SHOE COMPANY, INC., Describes a footwear and its manufacturing method. The shoe includes a shovel having a headliner with a tip part disposed along an inner surface of the blade. A relatively stiff insole front member is attached to an inner liner, the length of the front of the stencil being less than the length of the inner liner. The tip portion of the head liner is then sewn to a peripheral edge of the insole front part, the head liner and the insole front part define a cavity to receive a potion from a user's foot. A steel tip is then placed substally around the tip part of the headliner. The Spanish model No. 1062608, refers to an ergonomic shoe, the type of those located between the cut and the lining thereof, and at the level of the toe and heel, incorporate a rigid front stop and a rear buttress, which participate both in the assembly of the cut and in the protection of the foot against external impacts, characterized in that in correspondence with the stop and the buttress incorporates separate damping elements, adapted to the internal face of the stop and abutment and these as set the latter between the cut and the liner, said cushioning elements being a soft material of high density, such as a foam of urethane, polyurethane, polyethylene, EVA, latex, silicone or other similar material with adequate density and breathability to the type of footwear. The Spanish model No. 1062609, refers to an ergonomic footwear, the type of those located between the cut and the lining thereof, and at the level of the toe or helmet and the heel, incorporate a rigid front stop and a rear buttress, they participate both in the assembly of the cut and in the protection of the foot against external impacts, characterized in that each of these elements, butt and buttress, have two layers of different density, namely an outer layer of very high density, which determines the same hardness and rigidity, and an inner layer of lower density, which is softer and more comfortable and which is going to come into contact with the foot through the lining of the footwear. The Spanish model No. 1065081, describes a reinforcing toe for safety footwear, which has a vaulted configuration and intended for mounting on the front of a safety footwear used in certain industries, is characterized in that it is constituted by two parts or pieces (1) and (2), the first of them rigid, of domed configuration, while the second part or piece (2) is made of flexible material, and is joined by injection molding on the back of the rigid piece (1), forming a continuity thereof. In the Spanish model No. 2105370, a toe for a shoe or safety boot is described, to provide a toe which is light and has sufficient strength, the toe is made of a composite material comprising a thermoplastic resin (7) reinforced with fiber and at least one wire mesh (4) having a size of 7 to 200 grids and included in the fiber reinforced thermoplastic resin. In a preferred embodiment of said Spanish model, the fiber reinforced thermoplastic resin comprises a thermoplastic layer (1) reinforced with long fiber having long fibers (5) of reinforcement incorporated therein and a thermoplastic layer (2) reinforced with short fiber that it has short fibers (6) of reinforcement incorporated therein, and the wire mesh (4) is included in the thermoplastic layer (2) reinforced with short fiber. The differences lie in the fact that the aforementioned models describe aspects such as the assembly system, some materials of which they are composed and protective inserts in the tip of the foot; however, they do not define the design and development of a specific helmet based on an anthropometric study and the parts to be protected in the foot, considering the ergonomic and functional aspects in various user activities, they do not relate the norm of evaluation of impact and compression results that they fulfill. In the above-described developments the use of a bridge that basically serves to anchor the hull due to the construction system is described, in the present invention this bridge does not exist. The dimensions are not the same (width, height and internal depth). The dimensions of the helmet of the invention are adapted to the morphology of the worker's foot and suitable construction materials were included in order not to take space away from the helmet that accommodates the space needs determined by the dimensions of the foot, considering the movements for the various user activities during the development of their activity. The helmet of the invention has a fade in the contour or edge of the eyebrow, designed to accommodate a fader and create comfort in addition to improving the appearance of the footwear and disclosed in these documents does not present. The design of the invention withstands impact tests of approximately 101.7 to 146.7 Joules (10.40 to 14.95 kgf-m) and compression of 11130 to 14710 Newton (1135 to 1500 kgf-m), leaving a clearance of approximately 11.0 mm to 14.0 mm, in finished shoe and not only on the tip of the helmet. The invention relates to a one-piece helmet for safety and protection footwear, formed by a front wall with side walls connected on both sides and whose upper edges are joined to a concave surface and where the lower edges are provided with an eyebrow that gives rigidity, anchoring, stability and a base that also minimizes the movement of the hull and its collapse on the surface plant - sole - at the moment of receiving an impact or compression and at the same time it serves to join the helmet to the plant. In the case of the present invention, the safety footwear worn during work is provided with a helmet to prevent damage to the front of the foot, covering the five fingers thereof, by forces of sudden effect, such as objects that they fall. We searched the state of the art, without results, a helmet that would provide coverage and protection to the five toes of the foot and that was stable, light, comfortable and that under maximum impact, avoid injuries to the five toes and that out of simple manufacturing. This need is only covered by the helmet of the present invention which is formed in one piece, whose material provides resistance to impact and is stable and lightweight. In its design an elongated terminal part and an edge in the lower area have been incorporated, as a termination of the front and side walls while giving rigidity to the terminal corner. The hull is of a single piece without any perforation for means of subjection, with lateral walls and continuous plate, with a disposition of sufficient space for to correctly lodge the five toes of the foot and at the same time allow the free flexion of the same, offering a comfort that the commercial helmets do not offer. In the present invention, this helmet has a sharp edge termination which forms a framework in the form of an unusually rigid frame and resistant against impact forces. Another additional advantage that it presents is that since it is made up of a single piece, the placement of the covering material is facilitated, which can be for example leather, synthetic or textiles, improving the final appearance of the footwear. Another additional advantage is that the helmet can be manufactured in a single stage, and when produced on an industrial level, it provides important economic, technical, protection and health benefits. Still another advantage and that constitutes a difference with respect to the prior art is that slots or bars connected in articulated form are not needed to secure the helmet to the floor plate, thereby avoiding tensile stresses, which lead to deformation of industrial footwear and decreased protection of the foot, constituting, very contrary to its purpose, an element of undesirable risk.

Objects of the invention It is an object of the invention that from a last obtained by the anthropometric study of the worker user of safety and protection footwear and currently in the process of patenting by the same applicant of the present invention, a helmet is designed, calculated and elaborated. single piece to protect the five toes, defining heights, widths, depths and elements of balanced distribution of impact forces. Obtain a helmet that meets at least the tests of the NRF-008-PEMEX-2001 standard, impact resistance of 101.7 J (10.4 kgf - m) and compression of 11 130 N (1135 kgf - m). Develop a one-piece helmet that effectively protects the five toes of the foot, with the maximum possible comfort, without interfering with free flexion and that does not promote the deformation of the foot, which is ergonomic according to the morphology of the user of footwear. protection and security. Develop a one-piece helmet or effective protector of the five toes for proper use as personal protective equipment to reduce the economic and human costs that occur in the country due to injuries to the feet of workers who use this product.

Brief description of the figures Figure 1A is a top view showing the D-D line 'base of the helmet design and which allows the effective protection of the five toes. Figure IB is a top plan view of the foot in which the different measurements and parts of the foot involved in the design of the last and the helmet of the present invention are indicated. Figure 2A is a top plan view showing the position of the helmet with respect to the bones of the foot and some points used to determine the design and dimensions of the helmet. Figure 2B is a schematic view in lateral elevation of the last on which the different measurement lines and references are drawn to design and calculate the hull of the present invention. Figure 3 is a longitudinal sectional view of the line D-D 'of Figure 1A. Figure 4 is a view of the last of the preferred embodiment and its corresponding plan view illustrating measurement points of the helmet of the present invention, in which the location of the lower line of line D-D 'is shown, and the line P-C that defines the width of the last for the helmet design.

Figure 5 is a front isometric view of the helmet and where the internal vault thereof can be seen. Figure 6 represents a side elevational view illustrating the overall height and shape of the helmet. Figure 7 is a top plan view of the hull, in which the angles formed with respect to a straight line of the internal points of the width of the hull between the internal and external point equivalent to about 5 ° degrees can be seen as resulting from the coverage for the 1st and 5th fingers which gives better coverage to the 5th finger (little finger). Figure 8 is a sectional view taken on the center line of the last transferred to the helmet of figure 1A, where the detail of the step for the helmet vanishing is shown. Figure 9 is a view taken from the opposite side of the tip of the helmet. Figure 10 is a cross-sectional view following the line B-B 'of figure 9. The previous views show only the corresponding views of the right foot by simplification of illustration and explanation of the invention.

DETAILED DESCRIPTION OF THE INVENTION The helmet of the present invention has as one of its main characteristics the fact of protecting the 5 toes of the foot. To cover and protect the five toes of the foot, the following points must be taken into account during the design and calculation: 1. - Respect the bending line. 2. - Consider the external length of the fader. 3. - The anatomical distribution of the heads with the metatarsals. 4. - The inclusion of the 5 fingers. 5. - The displacement of the foot in march. 6. - Thickness of footwear construction materials The analysis of the flexion area of the fingers, the position of the metatarsal heads and the previous considerations allow to establish the anatomical aspects of the foot for the development of a protective helmet under a specific shape that covers the five fingers and that at the same time provides an area of sufficient flexion so that the helmet does not hit the metatarsal heads of the foot. It should be noted that the rim of the helmet of the present invention has two angles (a, ß) as shown in FIGS.

Figures 6 and 7, the hulls of the state of the art does not include these angles, which has repercussions in avoiding the flexion of the foot while at least partially protecting the 5 toes of the foot. To achieve the objects of the invention, that is, to obtain a one-piece helmet protecting the five toes for use in a protective footwear that effectively complies with said protection, that does not deform it, that is free of asperities, edges, tips, that is ergonomic and that at the same time the user can carry out normally the activity that exposes him to the risks with the appropriate protection and in the level that he requires, the present helmet is manufactured with materials that have no effects harmful to health. The helmet is one piece non-metallic although in an alternate mode it can also be made of a metallic material. As seen in Figure 3, the hull comprises an edge (11) formed by a front wall (5), side walls (6, 8) joined to the top by means of a portion of the non-planar surface (12) . The lower part of the helmet has an eyebrow (13) which is attached to the shoe through the plant (7). The opposite end of the non-planar surface (12) terminates in the rear wall (14) (see Fig. 6j_) This edge (11) fades from the front wall (5) towards the rear wall (14), by the face inner helmet, to finish on the step (18) (figure 8, 10) at a distance of typically 0.8 - 1.0 cm. Figures 8 and 10 are cross-sectional and longitudinal views showing the step (18). The rear wall (14) is a semi-cylindrical wall that generally follows the shape of a rounded tip, the edge joining the side walls (6, 8), the rear wall (14) and the top surface (12) is a rounded edge (figure 3). The design of the hull of the present invention forms a framework that due to the disposition in the space and the development of the corners, it is extraordinarily rigid and resistant against impacts. Due to the design of the helmet, the elements (4, 6, 8 and 11) and the eyebrow (13) and their ends ending in tip, drive the force of the impact on the walls to the sole, preventing the fingers from being exposed to the impact . Additionally, the eyebrow (13) avoids the penetrating action towards the contact surface, helmet-floor-sole, reducing the risk to the 5 fingers of the user of the safety and protection footwear. It also avoids the movement of the helmet at the moment of receiving an impact or compression of force defined in the aforementioned ranges (figures 3 and 5). In order to calculate the shape of the hull of the present invention, the last of the patent application file No. MX / a / 2007/003886 is used as the basis, whose holder is the same as that of the present application. This last, derived from an anthropometric study, allowed the perfect adaptation to the morphology of the worker user of safety and protection footwear. Therefore, the design of the protective helmet bases the definition of its dimensions on the last corresponding to the shoe size. It is not a universal helmet in the sense of not varying its measurements according to the footwear but its dimensions are modified according to the size of the footwear to which it will be adapted, which does not happen in the helmets of the state of the art. The variables that were considered for the elaboration of the last of industrial footwear were to see figure IB, in general: strong (R), width of the foot (AP), circumference of the instep (CE), width of heel (T), length of the instep (LE), dimensions of the toes, fibular length of the instep (LFEm), height of the recio (AR) (height of the circumference of the ball of the foot), height of the instep (AE), angle of the big toe (ag), little finger angle (am), foot length (LP), instep length (LE), foot length 16% (LPi6), foot length 50% (LP50), a certain tolerance, width and metatarsal length, plantar length and width, tip height, heel width (AT), finger area circumference (CAD), heel pear width, etc.

Additional considerations for the design of the last in the part of the tip that will define the design of the helmet are: the anatomical distribution of the heads of the metatarsals, the inclusion of the 5 fingers, the displacement of the foot in motion, the flexion area of the foot. The values obtained in the sample of the anthropometric study determined the dimensions applied specifically to the tip of the last so the design of the helmet will take as a basis the dimensions of it. It is important to point out that from a study to determine the coverage or protection capacity of the hulls with respect to the fingers, it was found that in the designs of the state of the art, the five toes are not protected but only four, leaving the discovered the smallest and therefore most fragile toe of the foot. Hence the need to design a helmet that covered this last finger. During the search, some inconveniences were found, such as the fact that by lengthening the depth of the hull, the mobility of the foot was restricted, imparting a very uncomfortable use. Therefore, some additional considerations for dimensioning and designing the helmet of the present invention were taken into account. Other considerations for the calculation and design of the helmet are: the thickness of the materials for the plant (E7), the thickness of the lining (E5) to be used, the thickness of the fade-off (no shown), as well as the dimensions of the last (Fig. 1A), as shown in Figures 2A, 2B and 3. An additional protective space has been added to the last for length and height in order to give freedom of movement to the fingers and create a space of grace in the case of a mishap of compression or impact to which the fingers may be subject, this consideration is an additional 3 to 7 mm. There are many other considerations to calculate the final dimensions of the protective helmet; however, the most important part that made it possible to achieve the objective of the present application is the shape of the contour that will follow the edge (11) of the hull which, to calculate it, was taken into consideration: 1. The point of depth suitable for bending was obtained in addition to the mathematical model when submitting the industrial shoe to the functions of walking and bending. 2. The dimensions of the toes, which were determined by using the three-dimensional scanning system called INFOOT, transferring the files using an adapter called LINE CONVERTER to a dimensional assessment system called RHINOCEROS. The transformation of the information to RHINOCEROS allowed us to accurately evaluate the three-dimensional dimensions of the fingers and thus establish the design criteria of the tip of the last and consequently those of the helmet.

The information obtained from the population evaluated by the three-dimensional measurement system through the INFOOT is subjected to statistical analysis to determine the trends of the measures and obtain the most representative for the population segments studied. The elaboration and use of a footwear constructed with the initial models of the hull and translucent materials that make it transparent and the recommendations established in the various studies carried out regarding the design of the footwear, established the criteria to determine the depth measurements of the helmet or toe protection, such as performing with the footwear different activities that may generate discomfort in the foot, such as squatting to perform an activity and test if the depth of the helmet is exceeded. In this case, the discomfort generated would be detected in the flexion zone. 3. The width of the helmet of a single piece is directly provided by the measures that show the anthropometric study where it is possible to establish the measurements of the toes and their set moved to the measures of the last. 4. Starting from the electronic capture of the last by means of the auxiliary software of design (called RHINOCEROS), where the images of the bodies of the previously designed lasts were captured, this system allows to work in detail the design and measurements of the parts and components that are of interest. In this way and given that the starting point of the design of the helmet or protective toe is the last, the basic measurements that will be corresponding to those of the hull are first established: width, height and depth. Once the points on the last have been identified and identified, a primary extraction of the helmet is made, obtaining an image as if we were to replicate an exact image of the tip of the last with the dimensions of the desired depth. On the lines defined for the width, height and depth defined in the last the additional advantages that are required to absorb in the design the dimensions and thickness of the plant, vanishing and lining are determined. By means of the electronic file that has been generated of each one of the designs and sizes of the helmet, the established dimensions can be established correctly, these are: interior dimension, central elevation, exterior elevation, elevation elevation and wide elevation, all these measurements are of hull interiors 5. The width of the helmet is directly proportioned with the measurements that the anthropometric study shows, from where it is possible to establish the measurements of the toes and their set, to transfer to the last the location of the metatarsal heads of the five fingers. locate the points (g) and (a) (see figure 2A) that are the internal and external fibular lengths of the last; for the determination of the curved line A joining said points. 6. To cover the fingers 1 (big toe) and 5 (pinky) of the foot in the best way (See figure 2A), without interfering in the flexion of the foot, the points of fingers 1 and 5 are projected in the curve DD 'towards the footing base of the last with a suitable angle of inclination so that it covers the mentioned fingers without generating friction in them and to give greater stability to the helmet by means of this design, establishing in this way in the base of the last two points that will be identified as P and C. The measurement of a straight line that joins the points P and C will determine the width of the last for the hull (the width of the last determines the width of the hull), to this measure will be added two Sometimes the thickness of the lining and twice the thickness of the fader so that the insertion of the helmet on the mounted footwear is correct.

Electronic adjustment of the design of the helmet to the electronic last.

Once adjustments have been made to the image originally extracted from the last, it is verified that the adapted measurements fit correctly with the electronic image of the last dressed. In this step, you can evaluate in detail If the measures of the helmet designed coincide with those of the last dressed or in its defect make the corrections of the deviations found and repeat the assessment, even though due to the accuracy of the software this is seldom feasible since the electronic systems of design in CAD environments have millimeter precision, as is the case of RHINOCEROS. It is possible to predict with good accuracy if the adjustments applied to the original dimensions of the helmet will have a correct adjustment since the original body of the last can be added the dimensions of floor thicknesses, fade and liner and simulate electronically if the adjustment will be correct . Given that helmets or protective toes are made in three types with respect to their base of support it is important to define in the design the type of base suitable for the operational effects of this helmet, the types of livelihood are: 1. without eyebrow 2. half eyebrow 3. full eyebrow. The helmet support base selected for the present invention is the full eyebrow (13). Once you have the final dimensions and the electronic file has been evaluated, it is sent to a prototyping area where the details are reviewed to: 1. - Develop the program of execution of the electronic design to the design in the numerical control center (CNC). 2. - Make adjustments to match the dimensions of the electronic design of the helmet with the dimensions of the electronic design of the mold. 3. Calculate the external dimensions required by the helmet design to meet the specifications of the established standard. 4. By designing an experiment design, dimensional variables that have a high probability of complying with the results of the experimental design and finally of the reference standard are determined. 5. The dimensionality and formulation are obtained, as well as all the processing conditions with which the compliance with the specifications was obtained in order to generate the industrial reproducibility of the helmet. 6. With certified helmets shoes are made to assess two fundamental aspects: a) Functionality of the design in use, evaluating the freedom of movement in various positions and user activities without the design interfere in any way with them. b) Laboratory tests to assess compliance in full footwear and to determine if the helmet or the construction of the footwear require adjustments.

Determination of the curvature D-D 'of the edge (11): To calculate the curvature of the edge (11), defined by the line DD '(see figure 1A and 2A) the following methodology has been followed: 1. - The actual length (10) of the last is determined by locating the central part of the heel and tip on the last plant (1) and the central part of the tip of the last; once the points are located, a measurement is taken following the contours of the foot shape of the last, by means of this operation the "L" value of the last is obtained as shown in figure 4. 2. - The line of the axis is traced upper center locating the points of the line from the central part of the table to the central point of the tip of the last. 3. - A value of L / 6.416 is obtained and applied to the body of the last measuring from a perpendicular line, drawn on the edge of the last of the last and following the line of the central axis, until locating the resulting value of L / 6.416. Additionally, the T / 3 value should be considered, which should be measured from a straight line parallel to the internal fibular that touches the point of flexion line A until it is equal to the point defined by L / 6.416 so that in this way considering as coordinates (L / 6. 16, T / 3) determine point P2 as one of the determining points of the curvature D-D '(figures 1A, IB, 3 and 6). Considering that: a) For the fifth finger (little finger) (P4): it is only covered up to the area of the nail equivalent to a quarter of the length of the finger, since to cover a larger area, it would create a friction effect of the walls of the helmet with the natural movement of the foot. b) For the first finger (fat) (Pl): coverage is given up to the flexion zone of the second metatarsal to avoid the aforementioned effect. Drawing a line between Pl, P2, P3 and P4, the curvature of the helmet that will effectively cover the five toes of the foot is defined, respecting the flexion zone. According to the locations of points Pl and P4, the following formula was developed to calculate the edge curvature (11): K = T / 3 + 5mm + 10mm, where: K is a constant that defines the point that is coinciding with the center line (10) of the last (1) and with the central line of the curvature of the helmet. Mathematically it is defined as the distance A - P3 (see figure 1A) which is equal to 1/3 of T + 5 mm + 10 mm.

T is the width of the heel. Pl is defined as the point on the curve of the hull closest to the line of descent on the last on the side wall towards the first finger (big toe). P2 is defined as the maximum point of the curvature more pronounced towards the curvature of the last. P3 is the distance where the curvature of the helmet coincides with the central axis of the last. P4 is the point closest to the line of descent towards the area of the fifth finger (little finger) or external line of the last. Having defined the elements contained in the formula for K, the location formulas for Pl to P4 for knight would be as follows: Pl = K- (0 to 7 mm) P2 = K + (0 to 6 mm) P3 = K P4 = K - (-1 to 2 mm), and for women: Pl = K- (9 to 12 mm) P2 = K - (1 to 3 mm) P3 = K P4 = K + (2 to 7 mm). For the other dimensions, an image editing program was used to visualize the position in the last, in a more objective way. the 5 metatarsal heads of the foot adjusting the points a-g as the points that determine the position "A" or line starts bending, see figure 2A. In the previous image, the position of the metatarsal heads of the skeletal system of the foot (b, c, d, e and f) can be observed, locating the points of the internal fibular length lines LFI and the external fibular length (LFE), correlating respectively the points ((a) and (g)) and finally joining said points, a shape is determined with special curvatures defining the flex area in the last. From here, it has been split to determine the following dimensions: - Dimensions of the last in the D-D 'zone: Zone D is the curvature on the hull last and it is at the highest point that the height must be considered. R = Maximum height of the last in the zone "D" (without considering the pump) Z = Maximum width of the last in the base plantar of the zone "D" And considering: Thickness of materials: Figure 3 shows the measurements Plant thickness (E7) Lining thickness (E5) Fading thickness (E4) Then the first dimensional determinations would be: Hull width (E2) Hull height (E9) So : (E2) = Z + 2 (E5) + 2 (E4) (without considering the pump of the last).

(E9) = R + (E7) + 2 (E5) + 2 (E4) (without considering the pump of the last).

Figures 1A, IB, 2A and 4 show the location of the lower line of the region DD 'is a region that defines a curvature symmetrical to the curvature of the metatarsal heads of the fingers, a point where the line intersects central of the last with the shape of the curvature designated as K or P3, two points called Pl and P4 that define the points in the curve D closest to the lateral walls of the last in the area of the 1st and 5th metatarsal running lines towards the bottom on the edge of the floor called P and C, the union of these two points P and C by a line of union determines the length of the last to calculate the helmet. The next step is to determine the line of the last of the last, for which a tangential point is drawn on the last of the last (TT) and a tangential point is drawn on the end of the last (PT), a line is drawn of union between TT and PT (figure 4) which determines the line of the last of the last in combination with the line of hull width, the external depths (PE), central (PC), internal (PI) (As it is shown in figure 4). Then divide this PC line by 4 to obtain the reference points for the external depth measurement of the last for the helmet, the central depth of the last for the helmet and the internal depth of the last for the helmet, to those points it will call them XI, X2 and X3, see figure 4. Parallel to the axis of the last lines are drawn from XI, X2 and X3, up to the points of the tip of the last in the base plan Yl, Y2 and Y3, forming in this way the lines that define the following depths of the last with respect to the hull: External depth of the last the distance measured in the last from XI to Yl The central depth of the last the distance measured in the last from X2 to Y2 The internal depth of the last the distance measured in the last from X3 to Y3 So : PEH = External depth of the last.

PCH = Central depth of the last. = X2-Y2 PIH = Internal depth of the last = X3-Y3 Ib. The depths of the hull are determined by the following formulas: PEC = External depth of the hull with respect to its internal dome. PCC = Central Depth of the Helmet with respect to its internal vault. PIC = Internal Depth of the Helmet of its inner vault.

So : PEC = PEH + E5 PCC = PCH + E5 PIC = PIH + E5 Xc. - Determination of the heel length The tangential point of the outer shell of the last is determined, once this point is determined, a flexible band is taken and a parallel line "T" is run and this line is marked on the last taking simultaneously the length of this, once the line "T" has been drawn, this length is divided by 3, as shown in figure 4, in this way an auxiliary T / 3 value is obtained to determine the flexion lines of the fingers.

Id.- Determination of the point A or height of the mouth Once the internal and external tangential points of the last in the area of the tip have been determined, a tape measure is passed around the body of the last and the point "A" is determined at the intersection of the center axis line (10) as shown in figure 1A, 2B and. him - Determination of the point BA starting from the point "A" and on the line of the central axis the value of T / 3 is added to this new measure, known as the point "B", this determination is based on the criteria of golden proportions of the morphology of the foot (see figures 2A, 2B and 4).

? £. - Determination of the point C Once the point B is determined, 5 mm are added on the line of the central axis (10) figures 1A and 4. The criterion of the 5 mm granted, has been determined as a result of the location of the flexion zone of the foot transferred to the last. Determining with this the point C where the line of flexion of the toes moved to the last is located (Figures 2A and 2B).

Ig.- Determination of point D In the construction process where the protective helmet is used, the element called fade is used, which is a synthetic material tape composed of two parts, one inserted into the edge or mouth of the helmet and has a small step of 1 mm thick and a width of 10 mm, towards the outside of the strip is a measure of 10 mm and overall the strip fade has a width of 20 mm. To determine the point D it is important to measure this element called fade at two specific points that are the inner eyebrow (18) and the outer eyebrow or edge (11) (see Figs 8 and 9) in this case the fader to be used has a total dimension (x) of 8 to 10 mm. Considering that the distance A-D is the area of flexion of the fingers, the distance to be added in the line of the central axis (10) after the point (C) is equal to the width outside the distance of (C) (all of Fig. 2A and B) to this is added from 8 to 10 mm and we determine the point P3 of the curve (D) (Fig. Al).

Ih.- Determination of width and height for the helmet design It has already been explained from the last the definition and position of the shape and position of the curve point "D" now making a longitudinal cut of the position "D" we will obtain the following image figure 3 ? ± .- Definition of hull angles In figure 6, the angle a that defines the angle between the maximum point of height of the region "D" and the line of support of the eyebrow is represented, said angle corresponds to 20 ° degrees , this allows additional stability of the hull giving anti-rolling properties and greater dispersion of efforts in the impact and compression tests. In figure 7, the angle ß is observed that is formed with respect to a straight line of the internal points of the hull width between the internal and external point, equivalent to 5 degrees as a result of the coverage for fingers Io and 5o with which gives better coverage to the fifth finger.

Claims

CLAIMS 1. A helmet of industrial footwear for protection of the toes, in one piece, characterized because the design of the helmet allows the protection of the 5 toes of the foot and because it forms a rigid and impact resistant frame according to the NRF standard -008-PEMEX-2001.
2. A helmet for the protection of the five toes, in one piece, in accordance with claim 1, characterized in that it comprises a front wall (5), side walls (6, 8) joined at the top by means of of the non-planar surface (12), an eyebrow (13), an edge (11) joining the side walls (6 and 8) and the top surface (12), a step (18).
3. A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that the edge (11) on the upper part and the eyebrow (13) on the lower part, and its Finished ends in tip, they drive the force of the impact on the walls until the sole, avoiding that the fingers are exposed to the impact.
4. A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that the eyebrow (13) prevents the penetrating action towards the contact surface, helmet-sole-sole, decreasing the risk to the 5 fingers of the user of safety and protection footwear.
5. A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that the edge (11) fades towards the front wall to end at the step (18) at a distance (x) ) from 0.8 to 1.0 cm.
6. A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that the edge joining the side walls (6, 8), the rear (14) and the top surface (12) is a rounded edge.
7. A helmet for the protection of the five toes, in one piece, according to the preceding claims, characterized in that the front wall (14) is a semi-cylindrical wall that generally follows the shape of a rounded tip.
8. - A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that the location for Pl a P4 is defined by means of the following mathematical formulas: For men: Pl = K- (0 to 7 mm) P2 = K + (0 to 6 mm) P3 = K P4 = K - (-1 to 2 mm), For lady: Pl = K- (9 to 12 mm) P2 = K - (1 to 3 mm) P3 = K P4 = K + (2 to 7 mm). Where K is a constant that defines the point that is coincident with the central line of the last and with the central line of the curvature of the helmet. Mathematically it is defined as the distance to P3 that is equal to 1/3 of T + 5 mm + 10 mm. T is the width of the heel. Pl is defined as the point on the curve of the hull closest to the line of descent on the last on the side wall towards the first finger (big toe). P2 is defined as the maximum point of the curvature more pronounced towards the curvature of the last. P3 is the distance where the curvature of the helmet coincides with the central axis of the last. P4 is the point closest to the line of descent towards the area of the fifth finger (little finger) or external line of the last.
9. A helmet for the protection of the five toes of the foot, in one piece, according to the preceding claims, characterized in that additionally it is adjusted for the location of the metatarsal heads of the fingers identified as Pl to P4, which are defined by means of the following mathematical formulas: (E2) = Z + 2 (E5) + 2 (E4) (without considering the of the last). (E9) = R + (E7) + 2 (E5) + 2 (E4) (without considering the pump of the last). Where: R = Maximum height of the last in the zone "D" (without considering the pump) Z = Maximum width of the last in the base of the zone "D" Plant thickness (E7) Thickness of the lining (E5) ) Fading thickness (E4) Hull width (E2) Hull height (E9)
10.- A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that it is additionally determines the depths of the hull, and that are defined by means of the following mathematical formulas: PEC = PEH + E5 PCC = PCH + E5 PIC = PIH + E5 Where: PEC = External depth of the hull with respect to its internal dome. PCC = Central Depth of the Helmet with respect to its internal vault. PIC = Internal Depth of the Helmet of its inner vault.
11. - A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that additionally the angle α of the helmet between the maximum point of height of the area "D" and the Support line of the eyebrow (13).
12. - A helmet for the protection of the five toes, one-piece, in accordance with the preceding claims, characterized in that the angle α of the helmet corresponds to 20 ° degrees, with a variation + -50%.
13. - A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that the angle α of the helmet allows a greater dispersion of efforts.
14. A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that the angle ß of the helmet that is determines with respect to the straight line of the internal points of the hull width between the internal and external point.
15. A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that the angle ß of the helmet corresponds to 5 ° degrees, with a variation of + -50%.
16. A helmet for the protection of the five toes, in one piece, in accordance with the preceding claims, characterized in that the angle ß of the helmet provides better coverage to the fifth finger.